Zookeeper-day03-API代码操作

最新推荐文章于 2025-12-05 10:16:32 发布

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本文介绍如何使用Java客户端连接ZooKeeper集群，并演示了基本操作，包括创建节点、获取子节点及监听变化等。此外，还展示了如何配置依赖项和日志记录。

1：添加pom文件内容

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-core</artifactId>
        <version>2.8.2</version>
    </dependency>
    <dependency>
        <groupId>org.apache.zookeeper</groupId>
        <artifactId>zookeeper</artifactId>
        <version>3.5.7</version>
    </dependency>
</dependencies>

2：resources目录下og4j.properties

log4j.rootLogger=INFO, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern =%d %p [%c] - %m%n
log4j.appender.logfile=org.apache.log4j.FileAppender
log4j.appender.logfile.File=target/spring.log
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n

3：创建zookeeper客户端并创建节点

package com.atguigu.zk;

import org.apache.zookeeper.*;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;

public class zkClient {

    private String connectString = "hadoop102:2181,hadoop103:2181,hadoop104:2181";
    private int sessionTimeout = 2000;
    private ZooKeeper zkClient;

    @Before
    public void init() throws IOException {

        zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
            public void process(WatchedEvent watchedEvent) {

            }
        });
    }

    @Test
    public void create() throws KeeperException, InterruptedException {
        String  nodeCreated= zkClient.create("/atguigu", "ss.avi".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    }

}

4：获取子节点并监听变化内容

package com.atguigu.zk;

import org.apache.zookeeper.*;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.util.List;

public class zkClient {

    private String connectString = "hadoop102:2181,hadoop103:2181,hadoop104:2181";
    private int sessionTimeout = 2000;
    private ZooKeeper zkClient;

    @Before
    public void init() throws IOException {

        zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
            public void process(WatchedEvent watchedEvent) {

                System.out.println("--------------------");
                List<String> children = null;
                try {
                    children = zkClient.getChildren("/", true);

                    for (String child : children) {
                        System.out.println(child);
                    }
                    System.out.println("-------------------");
                } catch (KeeperException e) {
                    e.printStackTrace();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }
        });
    }

    @Test
    public void getChildren() throws KeeperException, InterruptedException {
        //注册一次，生效一次

        //持续监听，监听到输出
        Thread.sleep(Long.MAX_VALUE);
    }

}

5：判断znode是否存在

@Test
public void exist() throws KeeperException, InterruptedException {
    Stat stat = zkClient.exists("/atguigu", false);

    System.out.println(stat==null? "not exist" : "exist");
}